[Tkinter] Make my button text update?

[Skata100]

So i have an integer 'bankValue' that is increased by a function 'addToBank'.

The buttons text displays 'bankValue', and should update upon click, but doesn't.

from tkinter import *
import tkinter.messagebox as mb
import os

# the in-game bank value, your total 'currency'
bankValue = 0

# function that decides how much to add to bankValue
def addToBank(amount):
    global bankValue
    bankValue += amount

# "gameWindow" = tk interface
gameWindow = Tk()

# heightxwidth of interface
gameWindow.geometry("500x250")

# title on top bar
gameWindow.title("WTFIT v0.05")

# button click = bankValue + amount (amount can be changed)
button1 = Button(gameWindow, command=addToBank(1), text=bankValue, width = 10, height = 2, bg = 'cyan')

# placement of button
button1.place(x=100, y=25)

# shows whats happening
gameWindow.mainloop()

I want the button to increase the value of 'bankValue', and display it as well.
I don't need it to display on the button either, if I can have that number display anywhere that would be awesome.


Thank you!
- Skata100

[deanhystad]

The easiest way to do this is make bankValue a StringVar or IntVar. In this example I make it a StringVar so I can format it to have two decimal places.

import tkinter as tk

def addToBank(amount):
    balance = float(bankValue.get()) + amount
    bankValue .set(f'{balance:.2f}')

gameWindow = tk.Tk()
bankValue = tk.StringVar()
bankValue.set('0.00')
button1 = tk.Button(gameWindow, command=lambda:addToBank(1.25), textvariable=bankValue)
button1.pack()

gameWindow.mainloop()

This code sets your callback function to None.

command=addToBank(1)

command is None because addToBank(1) calls the function and uses the return value (None) and the value for command. You probably wanted this:

command=addToBank

But this does not provide an argument for "amount" in addToBank(). You could get around this by providing a default value for amount.

def addToBank(amount=1.25):
    balance = float(bankValue.get()) + amount
    bankValue .set(f'{balance:.2f}')

You can also use a lambda expression to bind an argument to the function. The same kind of thing can be done using functools.partial